What are the working principle of the pneumatic valve

pneumatic valve opens, Blowdown process)
　　. Anticlockwise turn the handwheel pneumatic valve rod drives the pneumatic valve core gradually move up, release on sealing surface, the diversion on the pneumatic valve core gradually out of pneumatic valve seat inner hole, form a narrow gap, medium through pneumatic symmetric orifice on the seat into the pneumatic valve seat, a small amount of medium can flow through narrow slit, gradually reduce the system pressure.
　　. Continue to turn the handwheel counterclockwise, pneumatic valve core upward movement, guide seat remove pneumatic seat orifice of lumen, more through the medium of seat and pneumatic valve throttling after successful eduction.
　　. Continue to turn the handwheel counterclockwise, pneumatic valve core is up to the full open position, at this point, the medium pressure greatly reduced, a large number of impurities can be directly from the pneumatic valve set of orifice discharge, and the inverted the sealing seat of the vortex formation, keep clean the sealing surface, prevent adhesion of impurities on the seal.
pneumatic valve closing process:
. Clockwise (pneumatic valve, pneumatic valve rod drives the pneumatic valve core down, sewage at this time is over, the system pressure is low, pneumatic valve set on the orifice area gradually decreases, and guide sleeve close to the pneumatic valve seat, and the flow direction of medium change, medium after throttling at a certain speed through the pneumatic valve core and pneumatic valve sealing surface, gradually strengthen the strength of the sealing surface clean.
　　. Continue to turn the handwheel, pneumatic valve core on the diversion into the pneumatic valve seat inner hole, form the narrow gap throttling, because near the end of that medium has fewer impurities, the guide sleeve and pneumatic seat to prevent the narrow gap between the remaining small impurities into the sealing face, medium through the slit fast flow, thorough cleaning the sealing surface, guarantee seal contact with zero leakage.
　　. Continue to turn the handwheel, pneumatic valve core and the seal seat contact. Seal.
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